salimshah

After making the Ltuned suspension (springs + shocks) upgrade to 98 GS400 and Ltuned exhaust (should have little to do with my observations), the car behaves very well .... till I set the VSC off and floored it. The car behaved very differently and I had to fight it a bit to bring it under control.

Has anyone else experienced similar behavior?

Salim

gsintensive

Similar to most of the exhausts, You tend to lose a bit more back pressure, but you will gain better once in high end. My Lsportline exhaust is an exception, i felt a bit more hp as well in the low end (just my imagination?.... or? dunno = P)

Anywayz that's how it it = ) .....

disc108

exhausts, for the most part, are more for sound than for actual performance. id say they make about anywhere from 0-5 HP and it wouldnt make that big of a difference for a 300HP car. i think your newfound 'twitchiness' is from your l-tuned suspension.

bitkahuna

iTrader: (20)

I have not experienced any control issues but then I don't drive with VSC off - I figure it's cheap life insurance .

Can you describe in more detail what's happening? Is it wheel spin (that's probably it), is it while accelerating? Are you turning at all? If you're turning at all, stomping the gas, and don't have VSC on, that loss of control is called skidding.

salimshah

The road was not absolutely flat and I did not hear/smell the rear tires squeal.

My intention was to go straight but I had to adjust first right and then left (as I oversteerd). In any case I was surprised a bit. I have been going over the same road with VSC on and the car has always behaved right.

Salim

QBranchCars

Salim,

I assume you did a wheel alignment after your L-Tuned suspension install.

mooretorque

Salimshah, what speed were you going when you nailed it? Or were you launching from rest? It sounds like you lit up the rears enough to step the back end out a bit, which you then overcorrected (always easy to do) a small amount. Your account "as I oversteered" seems to suggest that you suspect this same explanation..........alternately, if you encountered some road irregularities such as truck ruts at the same time you jumped on it while at speed, you might be seeing some tramlining/hunting from the tires. What wheel/tire combination are you rolling on?

Qbranch and bitkahuna's responses are also equally valid possibilities.......but I have to disagree with disc; L-tuned shouldn't make your handling deteriorate in that fashion tho it might increase ride harshness (maybe "firmness" would be better term).

disc108

i was thinking along the lines of incorrectly aligned or something like that.

salimshah

Here is the complete setup:

Ltuned suspension (shocks + springs), 17" Dunlop SP2000 tires (new in rear, 5k front), Ltuned Steering ECU.

Start from a dead stop, full throttle (no power braking engine/tranny/wheels normal conditions ... 30+ minutes running) power mode, Road slightly rough but NO visible ruts. 4 wheel alignment done with installation of Ltuned suspension. Drive mode (not manual) 98 GS4 with 27K miles. ECU not reset for many miles/months => wife's car and is occasionally pushed when the official washer becomes the driver

For the cases I am trying to compare the only variable has been the VSC on or off. I did not hear the tires squeal ... maybe I was going super sonic speed

I will try it again and at different stretches of road and share my observations.

Salim

bitkahuna

iTrader: (20)

2000s? Never heard of 'em. Given that the other models (5000,8000,9000) go up in handling abilities, it implies 2000s would be pretty low on the handling scale. Maybe it's a tire problem?

salimshah

Almost ... tire -> tired problem.

You are right it they are 9000

I may have to take it back for alignment. The steering is not dead center. 15~20degrees ccw to go straight.

Salim